R (OM (Algeria)) v SSHD [2010] EWHC 65 (Admin)

OM was a failed asylum seeker facing deportation at the end of a criminal sentence. The Secretary of State's operational guidance stated that the mentally ill are normally considered suitable for detention in only very exceptional circumstances: he was unable to justify the detention according to this policy, and therefore it was unlawful. Detention was also unlawful because the claimant had not been notified of his in-country right of appeal.